1. Technical Field
The invention disclosed broadly relates to data processing systems and methods and more particularly relates to document image and coded data processing.
2. Related Patent
This patent application is related to U.S. Pat. No. 5,008,805 to Fiebig, et al., entitled "Real Time Fail Safe Process Control System and Method," assigned to, the IBM Corporation and incorporated herein by reference.
3. Background Art
High availability data processing applications such as process control in a factory environment, scheduling traffic and transportation networks, or scheduling and controlling operations in broadcast communications networks, or large volume financial transaction networks such as federal reserve applications, require a high reliability for the controlling processor. The prior art has provided high availability systems by employing redundant processors in a fail safe configuration wherein a first processor is the primary or active processor which provides actual control commands to the system being controlled and the system further includes a second or standby processor which monitors the operation of the active processor and is ready to take over primary operations in the event that a failure is detected in the active processor. This technique is called hot standby redundant processing.
A particular problem occurs where very large data files are being transferred over a local area network or a wide area network between data processing nodes. Because document image files, for example, are typically 50 Kbytes or larger, high bandwidth data communications networks are required for the communication of such large files between processing nodes. If one processing node suffers a failure and a second processing node in a standby function, steps in to substitute for the failed processor, the rerouting of large image files can present a communications bottleneck which forces an overall reduction in the throughput of large data files in the network.